• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.35-43
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• 2016

Recently, the pipeline system for waste transportation has been increasingly constructed as new solution for the waste collection and disposal system by constantly increasing domestic waste which issued as social problem. The pipeline system is constructed through long distance, so proper long-term monitoring system is necessary which available to detect the damage location for the effective maintenance. In this paper, the experimental study is carried out to evaluate the applicability of optical strain gauge sensor based on FBG for the long-term monitoring system. Three test parameters such as pressure leaking, blockage and deformation are considered as typical damages for real-scale pipeline test specimen. In order to measure flexural and volumetric strain and temperature, three FBG sensors are installed at each monitoring sections. From the test results, this study suggested effective methods of sensor installation and arrangement. Also the sensor spacing for the design of monitoring system using FBG sensor is derived by the correlation of distances from deformation between sensor responses.

• International Journal of Naval Architecture and Ocean Engineering
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• v.3 no.4
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• pp.233-241
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• 2011

The article describes actions and strategies to obtain higher productivity on maritime automobile terminals. The main focus is on elaboration of efficient and effective organizational structure to model and implement short-term, mid-term and long-term strategies. In addition, with an empiric approach we combined the analyses of current findings in important scientific papers and our acknowledgments in practical research of north Adriatic maritime automobile terminals. The main goal is to propose actions towards increasing system's productivity. Based on our research of the north Adriatic maritime automobile terminals and with Lambert's model an in-deep analysis of limiting factors, user's expectations and possibilities for productivity increase has been performed. Moreover, with our acknowledgments a three-level decision-support model is presented. With an adequate model implementation it is possible to efficiently develop and implement different strategies of productivity measurement and productivity increase, especially in the fields of internal transport productivity, entrance/exit truck gates operations and wagon manipulations. According to our observation a significant increase might be achieved in all three fields.

• Journal of the Korean GEO-environmental Society
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• v.16 no.10
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• pp.15-22
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• 2015

In this study, to evaluate the long-term behavior characteristics and the loss of prestress force, the long-term measurement of the tensile anchors in the actual construction was performed and the results were analyzed comparing with the existing estimation. As the reinforcement member used for the purpose of slope stability or uplift-resisting of the permanent structure, etc, the permanent anchor should maintain the functions during the performance period of the structure differently from the temporary anchor. However, as the time passes by, since the relaxation and the creep of the anchor occur constantly, the management for the loss of tensile force is essential to perform the functions stably. So far, the loss of the tensile force has been estimated according to the reduction of the prestress using elasticity theory and using the relaxation value according to the type of tension member and the test using the long-term measurement is limited. Therefore, in this study, the site condition and the ground were investigated for the tensile anchor in the actual construction and the long-term measurement results more than 500 days was analyzed by installing the loadcell, inclinometer and the groundwater level gauge. In addition, the long-term behavior characteristics were evaluated by comparing the disposition of the measured earth retaining wall and the tension force loss of the anchor with the existing interpretation results. In the evaluation results, the most of the tension force loss occurs within 90 days and the loss was measured less than the estimated values.

• Smart Structures and Systems
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• v.32 no.5
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• pp.297-308
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• 2023

Dynamic deflection is important for evaluating the performance of a long-span cable-stayed bridge, and its continuous measurement is still cumbersome. This study proposes a dynamic deflection monitoring method for cable-stayed bridge based on Bi-directional Long Short-term Memory (BiLSTM) neural network taking advantages of the characteristics of spatial variation of cable acceleration response (CAR) and main girder deflection response (MGDR). Firstly, the relationship between the spatial and temporal variation of the CAR and the MGDR is described based on the geometric deformation of the bridge. Then a data-driven relational model based on BiLSTM neural network is established using CAR and MGDR data, and it is further used to monitor the MGDR via measuring the CAR. Finally, numerical simulations and field test are conducted to verify the proposed method. The root mean squared error (RMSE) of the numerical simulations are less than 4 while the RMSE of the field test is 1.5782, which indicate that it provides a cost-effective and convenient method for real-time deflection monitoring of cable-stayed bridges.

• Journal of Korean Society of Transportation
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• v.30 no.2
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• pp.7-20
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• 2012

The objective of this paper is to construct pseudo-panel data set and estimate price and income elasticities of car travel demand, using 1995-2007 household income and expenditure survey data, in order to provide quantitative information for analyzing related policy effects in the transport sector. We categorized household survey data into 14 cohorts based on the birth year of the household head. As the result, a total of 133 pseudo-panel data sets was created for estimating price and income elasticities of car travel demand. Especially, price and income elasticities of car travel demand were separately estimated both short-term and long-term. We analyzed the panel model considering fixed effect within cohorts, using explanatory variables such as previous year's fuel consumption, real household income after tax, education level of the household head, the number of children under five, and the share of household type averaged by cohorts. As results, the short-term and long-term price elasticities of car travel demand were calculated as 0.2974-0.4280 and 0.4087-0.6275, respectively. Similarly, the short-term and long-term income elasticities were calculated as 0.3364-0.6281 and 0.7098, respectively.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1486-1493
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• 2012

In this study, we investigated whether galactooligosaccharide (GOS) can be stably and steadily synthesized using immobilized ${\beta}$-galactosidase (${\beta}$-gal) inclusion body (IB)-containing E. coli cells during long-term repeated-batch operation. To improve the operational stability of this enzyme reactor system, immobilized E. coli cells were crosslinked with glutaraldehyde (GA) after immobilization of the E. coli. When we treated with 2% GA for E. coli crosslinking, GOS production continued to an elapsed time of 576 h, in which seven batch runs were operated consecutively. GOS production ranged from 51.6 to 78.5 g/l ($71.2{\pm}10.5$ g/l, n = 7) during those batch operations. In contrast, when we crosslinked E. coli with 4% GA, GOS production ranged from 31.5 to 64.0 g/l ($52.3{\pm}10.8$, n = 4), and only four consecutive batch runs were operated. Although we did not use an industrial ${\beta}$-gal for GOS production, in which a thermophile is used routinely, this represents the longest operation time for GOS production using E. coli ${\beta}$-gal. Improved stability and durability of the cell immobilization system were achieved using the crosslinking protocol. This strategy could be directly applied to other microbial enzyme reactor systems using cell immobilization to extend the operation time and/or improve the reactor system stability.

• Journal of the Society of Disaster Information
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• v.8 no.3
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• pp.267-275
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• 2012

Long-term national railway building comprehensive review of the proposal had 100 in railway history, railway rail network plan. Planning routes for establishing a plan, but, considering the rail network, the plan was that could with the very important meaning in the What more economical route considering the costs and benefits of building a rail network under budget constraints, went through the process of background lines of business unit interval expenses to adopt a business unit interval. Especially in building the railway network, as well as the road plan was to reflect in order to build for the future railway facilities was secured examine the possibility of possible budget commitment. Budget of securing the transportation tax, gasoline tax, and other transportation facilities in order to secure and commit the current funding approach and Review Bodu possible budget scenarios based on it written. Was also enforce rail system built in reviewing the demand more than anything that can take advantage of the railway distance by railway and the merits of the competition means to compete in the form of the assumed situation. The rail network deployment plan, considering this was discussed, based on the results of the plan to establish the first annual or period of the plan change was based on the budget that was unknown.

• 한국ITS학회:학술대회논문집
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• 2005.11a
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• pp.83-88
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• 2005

A transportation problem in Korea is a serious issue that has to be solved urgently in the motor era of 15 million vehicles. Recently ITS has been introduced to improve efficiency of the current roads because an excessive budget and a long term construction are needed to build new roads. Therefore the government enacted the law as of ITS and the in architecture. However, these ITS information services were oriented to mainly vehicles and drivers, not public entities such as bus driver, passengers and so on. Nowadays lots of local autonomous city introduced a public transportation information system (PTIS), and providing useful information for the public. For this PTIS, important design issues are to be focused on detecting and tracking technology of moving bus, and a wireless communication link to transmit the location information. This paper presents design models using several wireless communication methods, and an implementation case using a Wireless packet Data communication Network (WDN) to transmit bus location information at Seoul, Korea.

• Journal of the Korean Geosynthetics Society
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• v.21 no.2
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• pp.11-19
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• 2022

In this paper, we propose a GoogleNet transfer learning and CNN-LSTM combination method to improve the time-series prediction performance for crack detection using crack data captured inside the sewer pipes. LSTM can solve the long-term dependency problem of CNN, so spatial and temporal characteristics can be considered at the same time. The predictive performance of the proposed method is excellent in all test variables as a result of comparing the RMSE(Root Mean Square Error) for time series sections using the crack data inside the sewer pipe. In addition, as a result of examining the prediction performance at the time of data generation, the proposed method was verified that it is effective in predicting crack detection by comparing with the existing CNN-only model. If the proposed method and experimental results obtained through this study are utilized, it can be applied in various fields such as the environment and humanities where time series data occurs frequently as well as crack data of concrete structures.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.561-572
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• 2021

This study aims to analyze the causality between GDP per capita, urbanization, and education. This also aims to determine the long-term and short-term relationships between economic urbanization, education, and GDP per capita by applying Vector Error Correction Model (VECM). Data was obtained from the World Bank and UNDP from 1990 to 2018. The estimation results showed that economic growth and education on urbanization have the strongest causality in VECM. Therefore, they are pull factors with a significant effect in the long and the short term. Some suggestions concerning policy implications were stated, and they include: forming area-based urbanization, where cities within one area are integrated, to get the impact of an agglomeration economy. Also, the government needs to accelerate the distribution of infrastructure and public facilities in various regions to avoid population density in one area due to urbanization, and government needs to pay attention to easier access to education and more equitable ones in various regions. On the contrary, after education is evenly distributed in all regions, the government needs to pay attention to transportation access and infrastructure.